Audience response systems enable groups of people, such as meeting participants, students, or audience members to vote wirelessly on a topic or to respond to questions submitted by a host, instructor, or presenter. Different audience response systems are known and have been used in numerous applications including education, audience participation, game shows, voting at conferences, opinion polls, and the like.
Various audience response systems include one or more base station RF transceivers. These base stations may be connected to a computer that may execute audience response system software. The base stations may also be adapted to communicate with several wireless keypads or other input devices adapted to enable a user to select a response to an inquiry. The base station transmits data inviting a response from the remote input devices. Audience members enter their responses to a question posed by the presenter by using their input devices. The audience responses are then communicated to the base station. The responses may then be stored, tallied, and/or displayed using the audience response system software.
Various transmission protocols, such as Wi-Fi, Cellular, wiMax, and Bluetooth are known in the art. All wireless transmissions operate within frequencies of the radio spectrum of the electromagnetic spectrum that are available for communication. These frequencies are treated as a public resource and are regulated by national organizations such as the Federal Communications Commission in the United States, or Ofcom in the United Kingdom. These agencies determine which frequency ranges can be used for what purpose and by whom. Wireless communication spans the spectrum from 9 kHz to 300 GHz. For example, Wi-Fi is a common wireless local area network using microwaves in the 2.4 GHz and 5 GHz bands that enables portable computing devices to connect easily to the Internet. Wi-Fi has become the de facto standard for access in private homes, within offices, and at public hotspots. Wi-Fi also allows communications directly from one device to another without an access point intermediary.
Because of the ubiquitous nature of radio transmissions, however, wireless transmissions often face problems with interference from other competing transmissions. For example, several other transmission protocols also operate within the operating frequencies of Wi-Fi including cordless telephones, baby monitors, Bluetooth devices, car alarms, and even microwave ovens.
Wireless communications typically include management and control information to support data transfer. A beacon sent from a base unit to a plurality of remote units enables a wireless system to maintain communications in an orderly fashion. The beacon may contain information about the network, and is transmitted by a base unit on a periodic basis. The time interval from the start of one beacon to the start of the next is called the beacon interval.